(Because I've had books where I've cleaned up/converted, forgot to change UUID, and the highlights carry over in all the wrong locations. After copying/pasting in new info, the old highlights disappeared.)

If that's true, surely it's using the epub's unique-id and not some random uuid included in the metadata being used, no? I would think the same issue would manifest regardless of what unique-id was used (uuid or ISBN or whathaveyou). In other words, there may be consequences for ANY unique-id value you forget to change/update.

I remember a couple years ago asking about a way to make Sigil regenerate a UUID because I was having problems with another app not recognizing that two epubs with same UUID were actually different books. I want to say it was Calibre but I'm not sure - other than Sigil and Calibre are pretty much the only 2 epub programs I use. Also, since I was made aware of the UUID concept, I make a new one each time....

Since most problems are 99.9% user error, I assume that was my problem in the Kindle Converter not converting the epub after I changed the code, even while EpubCheck validated it... KC might be a stickler with certain aspects of the code, and a little boo-boo in the wrong place could make it choke.

Out of curiosity, Tex, were the ebooks you bought that used ISBN for UUID epubs or an Amazon flavor? (If Amazon, that proves I did something wrong, imo.)

As to ISBN entry, I read that in this PDF from ISBN org, for entering info in metadata. This is also where I read the <Publisher> s/b the top level publisher, and if the book is published under an imprint, then <imprint> should also be present. This made sense since the portion of the ISBN that identifies the publisher only identifies the top level publisher, not its imprints.

However, I could not add dc:imprint to the metadata and have it turn out right. That is, once I converted with KC it showed my top level publisher as the publisher, and didn't even parse the imprint metadata at all, as seen in the conversion log.

About that time (yesterday afternoon) I started wondering if this PDF does not relate to epub metadata, but metadata entered on the Bowker site when registering ISBNs to a title, hence the name of the PDF.

Which would mean you can enter the ISBN with hyphens in epub meta and I don't need to add "dc:imprint" ... though that last one is more a worry since the ISBN 'won't match the imprint,' so ... it does seem like both s/b present .. ?

For any other readers regarding imprint and top level publishing name:

Reading more, it looks like the unique section of the publishing name in the ISBN will point to the top level publishing name, or to an imprint, if an imprint was selected in Bowker when the ISBN was selected for that title.

In other words, from my understanding, when Amazon (or a library or any entity) queries the Bowker (or ISBN) database, as long as the publisher listed in the metadata of the ebook matches the one selected in your Bowker acct, it should validate. Meaning, the dc:publisher metadata should be the imprint (vs the top level publisher), when that's applicable.

If someone more experienced knows better, please correct me.

Once I get this book up, if I get an error due to this assumption/understanding, I will come back and correct this myself. But I won't be uploading the book for a couple weeks yet.

@Tex2002ans Since I squared away the publishing/imprint stuff I went back a final time to try once again to make the UUID the ISBN, just 'cause that was bugging me. I carefully followed your instructions once more... and this time Kindle Previewer converted to mobi, no problem. So I did do something wrong the first several times. (Note to self: do code in mornings)